It is generally known to provide one or more protruding ground-engaging members on the sole of a shoe, especially on the sole of an athletic shoe for activities such as golf, soccer, track, baseball, and “American-style” football. Such ground-engaging members are variously known in the art as cleats, spikes, studs, leaves, blades, triangles, nubs, etc., and generally serve to increase traction between the shoe and the ground surface.
Furthermore, it is conventionally known to use particular types of ground-engaging members for certain types of playing surfaces. For example, molded cleats made from hard rubber or a thermoplastic material are commonly used on hard/firm natural ground surfaces (e.g., hard dirt). Relatively smaller molded rubber nubs are commonly used on artificial turf and the like. Also, relatively thin spikes are conventionally used in golf and in track.
For activities taking place on soft ground (e.g., wet fields, soggy grass, or muddy ground), it is generally known to use removable ground-engaging members. This is done to enable the user to use differed sized ground-engaging members based on the type of field being played on, and the condition of the field. Conventional removable ground-engaging members are typically engaged with a shoe sole by way of cooperating screw threads or other rotational engagement.
When conventional removable ground-engaging members are provided with screw threads for engagement with a shoe, a separate tool is used to manually rotate a ground-engaging member to attach and remove the ground-engaging members as desired. This is generally time consuming and labor intensive, and is also problematic if a user decides to change ground-engaging members in a hurried manner, such as during the course of a game, for example.
Furthermore, conventional removable ground-engaging members must be adequately rotationally tightened so as to ensure good engagement between the shoe and the ground-engaging member. However, it is conventionally difficult to recognize when the ground-engaging member has been adequately tightened. Thus, the ground-engaging member may be inadvertently over-torqued in an attempt to ensure good engagement. This can damage the screw threads on the shoe and/or on the ground-engaging member, making it difficult or even impossible to subsequently disengage the ground-engaging member from the shoe when desired. On the other hand, the ground-engaging member may be inadvertently under-torqued (for example, to avoid damage caused by over-torquing). When this occurs, the ground-engaging member may not function as a stable traction device and/or may become loose and be susceptible to falling off of the shoe.
While some conventional ground-engaging members are not threadedly engaged with a shoe, they still suffer from structural and/or functional problems. In particular, some existing non-threaded ground-engaging members are free to rotate relative to the sole. This can be a problem when, for example, the ground-engaging member is axially asymmetrical in shape (for example, conical or frusto-conical) because free edges of an axially asymmetrical ground-engaging member can become exposed, caught on objects and such, and be torn away. Furthermore, relative movement between a ground-engaging member and a sole generally destabilizes the engagement between the ground-engaging member and the sole, compared to holding them fixed relative to one another.
Also, some existing ground-engaging members use a receiving portion or the like mounted on an exterior surface of the shoe sole. Thus, the receiving portion may possibly be sheared off the sole or may otherwise become dislodged.